Successful Deployment of an Advanced Chemistry Enhanced Spacer Facilitates Cement Placement Under Difficult Conditions in Various Well Sections: A Compilation of Middle East Case Studies

Abstract The construction of oil and gas wells is often beset with complexities during critical phases such as drilling and cementing. This paper details the design, execution, and assessment of primary cementing in case studies involving intermediate & production sections, isolating weak and high-pressure zones under challenging conditions. An innovative wellbore shielding spacer, coupled with an environmentally friendly lost circulation material, was adopted with the Managed Pressure Cementing (MPC) technique, facilitating the placement of cement slurries and ensuring wellbore isolation. Three distinct cases where partial losses were encountered before the primary cementing operation across various formations. The wellbore shielding spacer acts by creating an impermeable barrier which in combination with a lost circulation material (LCM), increases the operational window by mitigating formation losses. This enables proper cement placement even when the Equivalent Circulating Density (ECD) slightly exceeds the fracture pressure. During execution, MPC was utilized to maintain downhole pressure and mitigate the losses. In the first case study, partial losses were encountered before executing the primary cement operation in the highly deviated section. With multiple potential weak formations to cover, the cement was successfully placed, controlling losses and achieving cement coverage up to the designed top of the cement. In the second case, a challenging interval with a narrow operating window of around 1 lb/gal under high-pressure, high-temperature (HPHT) conditions was drilled using managed pressure drilling to control losses and optimize response time while drilling. The risk of inducing additional losses increased during the primary cementing operation due to higher ECD. The MPC technique was employed to maintain a nearly constant (BHP), facilitating successful cement slurry placement across the interval. The third case involved a two-stage cement job with partial losses. The expected ECD during cementing surpassed the frac gradient, compromising cement placement as per design. However, after the first stage was completed, cement slurry was circulated to the surface up to the designed top of cement, ensuring full coverage across the open hole (OH). In all these case studies, the combination of the wellbore shielding spacer and the lost circulation additive proved to be an effective technology for addressing partial loss scenarios under challenging conditions. In all cases, the combined use of the wellbore shielding spacer and LCM proved effective in mitigating partial losses under challenging conditions. This approach enhanced formation integrity, reduced lost circulation, and enabled proper cement placement. Implementing this technology during critical well construction phases improved overall well integrity, minimized the need for costly remedial operations, and reduced the risk of production loss. It is particularly recommended for wells where the operating window is only marginally above the fracture gradient.